High homogeneity solenoidal magnet for cesium frequency standard

In Cs frequency standards a zone of highly uniform magnetic flux density, lower in value of 0.1 T, is required. The magnetic homogeneity value is tied to the overall accuracy of the standard and, for an accuracy of 10-14, a design value 1 p.p.m. is required. For this purpose a resistive solenoid 700 mm long with a bore radius of 32.5 mm has been designed and built. This paper reports the design process, the measurements on the manufactured magnet and the shimming strategy used to reach the homogeneity target

An Algorithm for the semi-analytical Computation of Fields emitted in layered Ground by HVDC Electrodes

For the design of HVDC ground electrodes it is of the utmost importance the availability of reliable and fast numerical tools, to evaluate both the fields and corrosion risk of nearby structures. Among the used algorithms, the Complex Images Method is well-known. However such method is often based on Prony\u2019s interpolator, which may show poor convergence properties, or even instability in particularly ill-conditioned cases. In this paper the use of a substitute interpolator, efficiently solving these drawbacks, named GPOF (Generalized Pencil Of Functions) is presented and results are discussed

MicroRNAs and Hematopoietic Differentiation

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Acetaldehyde binding energies: a coupled experimental and theoretical study

Acetaldehyde is one of the most common and abundant gaseous interstellar complex organic molecules, found in cold and hot regions of the molecular interstellar medium. Its presence in the gas-phase depends on the chemical formation and destruction routes, and its binding energy (BE) governs whether acetaldehyde remains frozen onto the interstellar dust grains or not. In this work, we report a combined study of the acetaldehyde BE obtained via laboratory TPD (Temperature Programmed Desorption) experiments and theoretical quantum chemical computations. BEs have been measured and computed as a pure acetaldehyde ice and as mixed with both polycrystalline and amorphous water ice. Both calculations and experiments found a BE distribution on amorphous solid water that covers the 4000--6000 K range, when a pre-exponential factor of $1.1\times 10^{18}s^{-1}$ is used for the interpretation of the experiments. We discuss in detail the importance of using a consistent couple of BE and pre-exponential factor values when comparing experiments and computations, as well as when introducing them in astrochemical models. Based on the comparison of the acetaldehyde BEs measured and computed in the present work with those of other species, we predict that acetaldehyde is less volatile than formaldehyde, but much more than water, methanol, ethanol, and formamide. We discuss the astrochemical implications of our findings and how recent astronomical high spatial resolution observations show a chemical differentiation involving acetaldehyde, which can easily explained as due to the different BEs of the observed molecules.Comment: 12 pages, 6 figure